JP4779543B2 - Electric throttle learning device - Google Patents

Description

  The present invention relates to an electric throttle learning device that learns the correlation between the opening of an electric throttle installed in an intake passage of an internal combustion engine and the amount of intake air of the internal combustion engine.

In Patent Document 1, during the idling operation of the internal combustion engine, the opening degree of the electric throttle is adjusted so that the actual intake air amount reaches the required value, and the throttle reference opening corresponding to the required intake air amount and the actual An intake air amount control device that learns the amount of deviation from the throttle opening as a throttle learning value and calculates a value obtained by correcting the throttle learning value based on the engine operating state as a correction value for the target throttle opening is disclosed. .
JP 2000-257490 A

As described above, the conventional learning control learns the correlation between the throttle opening and the intake air amount from the data when the throttle opening is normally controlled so that the required intake air amount can be obtained in the idling state. The information for determining the change in the correlation between the throttle opening and the intake air amount is limited to one point data in the normal control state.
For this reason, the estimation accuracy of the correlation in the area out of the normal control state is poor, and the change over time in the correlation between the opening degree and the intake air amount cannot be learned accurately in a wide area, and the characteristics over time There is a problem that it is difficult to maintain high control accuracy of the idle air amount against changes.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a learning device capable of accurately learning the correlation between the opening degree of the electric throttle and the intake air amount of the internal combustion engine in a wide region within the idle region. To do.

Therefore, the learning device for the electric throttle according to the present invention corrects the ignition timing of the internal combustion engine during the idling operation of the internal combustion engine and cancels the torque change due to the correction of the ignition timing so as to maintain the target idle rotation speed. In this way, the opening degree of the electric throttle is changed, and correlation data between the opening degree and the intake air amount is obtained at the changed opening degree, and the correction amount of the ignition timing is changed into a plurality of values. The correlation between the throttle opening and the intake air amount is learned based on a plurality of correlation data .

According to the above configuration, the output torque of the engine changes by correcting the ignition timing. Therefore, the amount of intake air of the engine is changed by changing the throttle opening so that the torque does not change.
This makes it possible to forcibly generate a throttle / intake air amount state different from the throttle opening / intake air amount state at the normal ignition timing, and to estimate and learn the correlation based on a plurality of data in the idle region. Thus, the correlation between the throttle opening and the intake air amount can be learned with high accuracy in a wide region within the idle region.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of an internal combustion engine for a vehicle according to an embodiment.
In FIG. 1, air that has passed through an air cleaner 2 is sucked into each cylinder of an internal combustion engine (gasoline engine) 1 through an intake duct 3, an intake collector 4, an intake manifold 5, and an intake valve 6.

The intake air amount of the internal combustion engine 1 is adjusted by an electric control throttle 7 interposed in the intake duct 3.
The electric throttle 7 is a mechanism for opening and closing a butterfly throttle valve 7a with a throttle motor (throttle actuator) 7b.
A fuel injection valve 9 is provided in each intake port portion of each cylinder.

The air-fuel mixture formed by the fuel (gasoline) injected from the fuel injection valve 9 is ignited and combusted by spark ignition by the spark plug 15 in the combustion chamber 10.
Each ignition plug 15 is directly attached with an ignition coil 16 incorporating a power transistor.
Note that the fuel injection valve 9 can directly inject fuel into the combustion chamber 10.

The combustion exhaust in the combustion chamber 10 is discharged to the atmosphere via an exhaust valve 11, an exhaust manifold 12, and an exhaust duct 13.
The exhaust duct 13 is provided with a catalytic converter 14 for purifying harmful components in the exhaust.
The power transistor for controlling energization to the throttle motor 8, the fuel injection valve 9, and the ignition coil 16 is controlled by an engine control unit (ECU) 21 incorporating a microcomputer.

Detection signals from various sensors are input to the engine control unit 21.
The various sensors include an air flow meter 22 that detects the intake air flow rate (mass flow rate) of the internal combustion engine 1 on the upstream side of the electric throttle 7, and an exhaust gas on the upstream side of the catalytic converter 14 based on the oxygen concentration in the exhaust gas. An air-fuel ratio sensor 23 that detects the air-fuel ratio, a rotation speed sensor 24 that detects the rotation speed of the internal combustion engine 1, an accelerator opening sensor 25 that detects the amount of depression of the accelerator pedal operated by the driver (accelerator opening), and the throttle A throttle sensor 26 for detecting the opening degree of the valve 7a is provided.

The engine control unit 21 controls the fuel injection amount by the fuel injection valve 9 as follows.
First, basic fuel injection for forming an air-fuel mixture with a target air-fuel ratio in the cylinder intake air amount at that time from the intake air flow rate detected by the air flow meter 22 and the engine rotational speed detected by the rotational speed sensor 24. While calculating the amount, various correction coefficients are calculated based on the coolant temperature of the internal combustion engine 1 and the air-fuel ratio feedback correction coefficient is set so that the air-fuel ratio detected by the air-fuel ratio sensor 23 approaches the target air-fuel ratio. The basic fuel injection amount is corrected with these correction coefficients, and the final fuel injection amount is set.

Then, an injection pulse signal having a pulse width corresponding to the final fuel injection amount is output to each fuel injection valve 9 in accordance with the stroke of each cylinder.
The engine control unit 21 calculates an ignition timing (ignition advance value) from the basic fuel injection amount (engine load) and the engine rotation speed, and the ignition coil based on the ignition timing and a predetermined energization time. The power transistor built in 16 is controlled to be turned on / off.

Further, the engine control unit 21 controls the intake air amount of the internal combustion engine 1 as follows.
During non-idle operation of the engine 1, a target intake air amount and further a target throttle opening are set based on a required torque corresponding to an accelerator pedal depression amount (accelerator opening) detected by the accelerator opening sensor 25. Then, the opening degree of the electric control throttle 7 is controlled based on the target throttle opening degree.

  Further, during idling operation of the engine 1, the idling basic air amount is set from the cooling water temperature and the auxiliary load, and the opening degree of the electric throttle 7 is feedforward controlled based on the idling basic air amount, The air amount during idling is feedback-corrected according to the deviation between the target idle speed set according to the operating conditions such as the cooling water temperature and the actual idle speed.

By the way, the correlation between the opening degree of the electric throttle 7 and the intake air amount changes with time, and the intake air amount obtained in the initial state cannot be obtained at the same opening degree. If the opening degree of the electric throttle 7 is feedforward controlled, the intake air amount cannot be controlled as required.
Therefore, in the present embodiment, the correlation between the throttle opening and the intake air amount is learned, and the target throttle opening is corrected based on the learning result. Details of the learning are according to the flowchart of FIG. This will be described in detail.

In the flowchart of FIG. 2, first, in step S <b> 1, it is determined whether or not the idling operation is performed when the accelerator is fully closed.
When the engine 1 is in the idling operation, the process proceeds to step S2, and it is determined whether or not the idling rotation feedback control is being performed and the engine rotation speed is stable at the target idle rotation speed.

When the target idle rotation speed is stable, the process proceeds to step S3, and the ignition timing is forcibly retarded by a predetermined amount.
In the next step S4, the opening degree of the electric throttle 7 is corrected to increase corresponding to the retardation correction.
If the ignition timing is retarded, the engine output torque is reduced and the idle rotation speed is reduced. As described above, the opening degree of the electric throttle 7 is feedback-controlled to maintain the target idle rotation speed. As a result, the throttle opening increases and changes so as to offset the torque drop (see FIG. 3).

In step S5, the correlation between the throttle opening detected by the throttle sensor 26 and the intake air amount detected by the air flow meter 22 is stored in the learning memory in a state where the ignition timing is corrected to be retarded.
In the next step S6, it is determined whether or not the combustion has become unstable (misfire has occurred) as a result of retarding the ignition timing, and the rotational fluctuation of the engine 1 is not less than a predetermined value.

If it is not determined in step S6 that rotation fluctuation has occurred, the process proceeds to step S7, where the total amount of retardation correction (the amount of retardation from the normal ignition timing to the current ignition timing) is set in advance as a learning limit value. It is determined whether or not.
If the total amount of retardation correction has not reached the learning limit value, the process returns to step S3, and the ignition timing is further retarded by a predetermined amount in addition to the retardation amount up to the previous time, thereby further reducing the throttle. The correlation between the opening degree and the intake air amount when the opening degree and the intake air amount are large is stored in the learning memory.

If it is determined in step S6 that the rotational fluctuation exceeding the predetermined value has occurred before the total retard amount of the ignition timing reaches the learning limit value, the retard correction is canceled in step S10 and the ignition timing is set. After the learning is stopped by returning to the normal value, the process returns to step S1.
Thereby, it is possible to avoid the deterioration of the combustibility of the engine 1 by learning control accompanied by the retardation correction of the ignition timing, and it is possible to prevent the catalytic converter 14 from deteriorating due to the afterburning of fuel due to misfire.

When canceling the retard correction and returning the ignition timing to the normal value, the retard correction amount is gradually decreased to gradually return to the normal ignition timing.
On the other hand, the retardation correction amount is gradually increased, and the correlation between the throttle opening and the intake air amount at that time is stored in the learning memory for each of the plurality of retardation correction amounts, and the total retardation amount reaches the limit value in step S7. If it is determined, the process proceeds to step S8 where the retard correction is canceled and the ignition timing is returned to the normal value.

In the next step S9, the correlation between the throttle opening and the intake air amount is updated based on the intake air amount data for each of the plurality of throttle openings stored in the learning memory.
In updating the correlation between the throttle opening and the intake air amount, from the intake air amount data corresponding to each of the plurality of throttle openings, the throttle opening and the intake air amount are calculated using, for example, the least square method. The correlation is updated (see FIG. 4).

Then, using the correlation between the updated opening degree and the intake air amount, an opening degree corresponding to the required intake air amount is obtained, and the electric throttle 7 is controlled.
As described above, according to the present embodiment, a plurality of pieces of correlation data between the throttle opening and the intake air amount are obtained on the higher opening (high air amount) side than the throttle opening in the normal idle control. The correlation between the throttle opening and the intake air amount is updated from a plurality of correlation data (see FIG. 4).

  Therefore, compared with the case where the correlation between the throttle opening and the intake air amount is updated from only one point data of the throttle opening and the intake air amount in the normal idle control state, it is discretely distributed in a wide idle region. The correlation between the opening and the intake air amount can be accurately updated from the obtained multiple data, and even if there is a change in characteristics over time, by controlling the throttle opening based on the updated correlation, The required intake air amount can be accurately controlled.

  The advance angle is corrected with respect to the normal ignition timing, and the throttle opening is decreased and changed so as to cancel out the torque increase due to the advance angle correction. It is also possible to learn the correlation between the ignition timing and the ignition timing on both the advance side and the retard side with the normal ignition timing as the center, and the throttle in the normal control state. The change direction and range of the ignition timing can also be determined from the opening.

The system figure of the internal combustion engine for vehicles in an embodiment. The flowchart which shows the learning process of the correlation with the throttle opening and intake air amount in embodiment. The time chart which shows the change of the ignition timing, throttle opening, and intake air amount at the time of learning in embodiment. The diagram which shows the update characteristic of the correlation with the throttle opening and intake air amount in embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Air cleaner, 3 ... Intake duct, 4 ... Intake collector, 5 ... Intake manifold, 6 ... Intake valve, 7 ... Throttle valve, 8 ... Throttle motor, 9 ... Fuel injection valve, 10 ... Combustion chamber, DESCRIPTION OF SYMBOLS 11 ... Exhaust valve, 12 ... Exhaust manifold, 13 ... Exhaust duct, 14 ... Catalytic converter, 21 ... Engine control unit, 22 ... Air flow meter, 23 ... Air-fuel ratio sensor, 24 ... Rotational speed sensor, 25 ... Accelerator opening sensor, 26 ... Throttle sensor

Claims (5)

An electric throttle learning device for learning a correlation between an opening degree of an electric throttle installed in an intake passage of the internal combustion engine and an intake air amount of the internal combustion engine,
During the idling operation of the internal combustion engine, the ignition timing of the internal combustion engine is corrected, and the opening degree of the electric throttle is changed so as to cancel the torque change due to the correction of the ignition timing so as to maintain the target idle rotation speed. Then, correlation data between the opening and the intake air amount is obtained at the changed opening, the correction amount of the ignition timing is changed to a plurality, and electric control is performed based on the plurality of correlation data obtained by each. A learning device for an electric throttle, which learns a correlation between a throttle opening and an intake air amount .   The ignition timing is corrected to retard, and the opening of the electric throttle is increased so as to compensate for the torque reduction due to the ignition timing retardation correction. The learning apparatus for an electric throttle according to claim 1, wherein the correlation is learned. 2. The correction of the ignition timing is canceled and the learning of the correlation between the opening degree and the intake air amount is stopped when a rotation fluctuation occurs in the internal combustion engine due to the correction of the ignition timing. Or the learning apparatus of the electric throttle according to 2 . Claim 1-3, characterized in said continue to gradually increase the correction amount of the ignition timing, until the correction amount reaches a predetermined learning threshold value, thereby continuing the learning of the correlation between the opening and the intake air amount The electronic throttle learning device according to any one of the above. When the opening degree of the electric throttle is feedback controlled so that the idle speed of the internal combustion engine matches the target idle speed, the ignition timing is corrected, and the opening degree of the electric throttle and the intake air amount are corrected. The learning device for an electric throttle according to any one of claims 1 to 4 , wherein the correlation is learned.

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